update Piwik to version 2.16 (fixes #91)

www/analytics/plugins/Provider/Archiver.php

@@ -1,6 +1,6 @@
 <?php
 /**
- * Piwik - Open source web analytics
+ * Piwik - free/libre analytics platform
  *
  * @link http://piwik.org
  * @license http://www.gnu.org/licenses/gpl-3.0.html GPL v3 or later
@@ -24,6 +24,16 @@ class Archiver extends \Piwik\Plugin\Archiver
 
     public function aggregateMultipleReports()
     {
-        $this->getProcessor()->aggregateDataTableRecords(array(self::PROVIDER_RECORD_NAME), $this->maximumRows);
+        $columnsAggregationOperation = null;
+
+        $this->getProcessor()->aggregateDataTableRecords(
+            array(self::PROVIDER_RECORD_NAME),
+            $this->maximumRows,
+            $maximumRowsInSubDataTable = null,
+            $columnToSortByBeforeTruncation = null,
+            $columnsAggregationOperation,
+            $columnsToRenameAfterAggregation = null,
+            $countRowsRecursive = array()
+        );
     }
 }